It has been conventionally performed to sound plural parts or timbres simultaneously when a user plays a keyboard in an electronic musical instrument. In particular, as a technique (hereinafter referred to as an “ensemble tone generating function”) to distribute notes having plural different tone pitches, which are inputted by simultaneous depressing of plural keys or the like, among plural parts or timbres to sound the notes in the plural parts, there is known an electronic musical instrument which assigns either plural parts or timbres to plural notes inputted by using a keyboard or the like to sound the notes in the respective parts or timbres. For example, in the electronic musical instrument of PTL1, in a unison-two mode, predetermined plural parts (four parts for example), which constitute a composition of musical instruments and to each of which plural different timbres are set, are assigned substantially evenly according to the tone pitch order to respective notes of keys being depressed, thereby allowing that even when the number of notes of keys being depressed changes, the total number of parts to be sounded does not change, and the respective parts are utilized evenly.
Further, in the electronic musical instrument of PTL2, there are provided plural assigners, which assign (correlate) notes of depressed keys to tone generation channels. Each assigner has settings of an assignment priority rule (for example, assignment method: higher-pitch-prior-to-lower-pitch, last-note-prior-to-first-note, lower-note-prior-to-higher-note), a number of notes to be sounded, and timbres (piano A, violin B, or the like). The electronic musical instrument uses plural assigners each of which has suitable settings (for example, an assignment priority rule to be applied, the maximum number of notes of depressed keys able to sound, and timbres to be used in the tone (sound) generation) to enable functions such as dual, split, and so on.
However, in the electronic musical instrument of PTL1 or PTL2, when plural keys are depressed (note-on input) simultaneously, if musical tones at different notes are sounded in respective parts or respective timbres, it is difficult to grasp what note of musical tones are sounded in what part or what timbre. Further, when the inputted notes themselves are not inputted by a user operation (key depression) but externally inputted or automatically generated, it is further difficult to grasp the tone generating status regarding what kind of tone generation is performed in respective parts or timbres with respect to what kind of input. Moreover, when it is difficult for a user to recognize tone generating status, hurdles for such users to set a tone generation assignment method and so on increase.
On the other hand, there has been known technologies related to display of a key depression state or the like. For example, NPL1 and NPL2 describe that, on a staff notation or keyboard displayed on a screen, positions of depressed keys are displayed as positions in the staff notation or the keyboard, a melody chord of a song (song data in MIDI format) is displayed, and notes constituting a chord are displayed (sections of “musical note display” and “keyboard display”). However, NPL1 does not disclose display of a tone generation state when plural parts or timbres are assigned to inputted plural notes to sound them.